Vaclav Smil on natural gas (ethane) and plastics

Vaclav Smil. 2013. Making the Modern World: Materials and Dematerialization.  Wiley.

Polyethylene (PE) is by far the most important thermoplastic (it accounted for 29% of the world’s aggregate plastic output, or roughly 77 Mt, in 2010), polypropylene (PP) comes next (with about 19% or 50 Mt in 2010), followed by polyvinyl chloride (PVC, about 12% or 32 Mt in 2010).

In 2010, packaging consumed almost 40% of the total (mostly as various kinds of PE and PP), construction about 20% (mostly for plastic sheets used as vapor barriers in wall and ceiling insulation), the auto industry claimed nearly 8% (interior trim, exterior parts), and the electrical and electronic industry took about 6% (mostly for insulation of wires and cables).

All of these products begin as ethane. In North America and the Middle East ethane is separated from natural gas, and low gas prices and abundant supply led to surplus production for export and favored further construction of new capacities: in 2012 Qatar launched the world’s largest LDPE plant and, largely as a result of shale gas extraction, new ethylene capacities are planned in the USA (Stephan, 2012). The dominant feedstock for ethane in Europe, where prices of imported natural gas are high, is naphtha derived by the distillation of crude oil.

Plastics have a limited lifespan in terms of functional integrity: even materials that are not in contact with earth or water do not remain in excellent shape for decades. Service spans are no more than 2–15 years for PE, 3–8 years for PP, and 7–10 years for polyurethane; among the common plastics only PVC can last two or three decades and thick PVC cold water pipes can last even longer (Berge, 2009).

Some products made out of plastic:

  • Transparent or opaque bags (sandwich, grocery, or garbage)
  • sheets (for covering crops and temporary greenhouses),
  • wraps (Saran, Cling)
  • squeeze bottles (for honey)
  • HDPE garbage cans
  • containers (for milk, detergents, motor oil)
  • HDPE for house wraps (Tyvek) and water pipes
  • PEX for water pipes and as insulation for electrical cables
  • UHMWPE for knee and hip replacements.
  • massive LDPE water tanks
  • indoor–outdoor carpeting
  • lightweight fabrics woven from PP yarn and used particularly for outdoor apparel
  • insulated wires, water, and sewage pipes to food wraps and her car’s interior and body undercoating
  • disposable and surgical gloves
  • flexible tubing for feeding
  • breathing and pressure monitoring, catheters
  • blood bags
  • IV containers
  • sterile packaging
  • trays
  • basins
  • bed pans and rails
  • thermal blankets
  • lab ware
  • construction (house sidings, window frames)
  • outdoor furniture
  • water hoses
  • office gadgets
  • toys
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